Interdental brush handles and brushes are well known in the dental industry, as described for example in U.S. Pat. Nos. 3,559,226, 4,222,143, and 4,387,479. Interdental brushes fit into spaces between and around the teeth and are generally used by people with special brushing needs such as, for example, people who wear dental bridges. Thus, a variety of interdental brush handles are available, including small, portable devices which fit easily into pockets or purses. These devices are generally rigid units with several pans that include handles, brushes integral with the handles, and often covers that slip over the brushes. However, the rigidity of prior art handles often interferes with the interdental cleaning process, particularly where visual contact is required. As a result, the rigid prior art interdental devices are generally inadequate for thorough or extensive interdental cleaning.
Thus, flexible, portable interdental brushes were introduced in an effort to decrease or eliminate problems associated with rigid devices. Two such flexible interdental brushes are shown in Japanese Utility Model Publications Nos. 63-3225 and 63-3226. In the first publication (63-3225), the interdental brash includes a bellowed portion of smaller cross-section which bifurcates the larger neck portion of the brush. The brush stem extends through the bifurcated neck and bellowed portion. The bellowed portion holds the brush stem and permits deflection of the stem to a desired angle. In the second publication (63-3226), the interdental brush includes a holding rod for holding a brush stem which is integrated with the handle of the brush. Both the holding rod and the brash stem may be deflected to a desired angle.
Another interdental brush is disclosed in U.S. Pat. No. 4,691,404. It includes a smooth, flexible tip end for easy access to the more remote or difficult to reach regions of the mouth. This interdental brush includes a selected amount of flexibility in the neck region at a junction between the handle and the brush stem which permits deflection of the neck to a desired brushing angle.
While the flexible interdental brush disclosed in U.S. Pat. No. 4,691,404 is effective in interdental cleaning, a problem sometimes arises during the manufacturing process of these brushes. The wire brush stem will sometimes protrude or become exposed along a side of the handle. This can occur during the injection molding process because the thin, flexible wire brush stems are molded under pressure into very narrow, tapered portions of the brush handles. The narrowness of these portions of the brush handles precludes any substantial movement of the wire brush stems within the handles without the resultant exposure of the wire stems. As a result, movement of the stems resulting from the pressure of the injection molding process must be carefully controlled. In addition, the tapered configuration of the brush handles contributes to the problems associated with exposed and protruding wire brush stems, especially in brush handles with varying angled or shaped sections. In such instances, the wire brush stems can become excessively exposed at the junction of the differently angled or shaped sections. Because interdental brushes with protruding wires may be unacceptable commercially, they must be discarded as waste thereby increasing scrap levels, labor, and operating costs in the manufacturing process.
Accordingly, an object of the present invention is to provide an interdental toothbrush which retains the functional characteristics of the brushes shown, for example, in U.S. Pat. No. 4,691,404, but which facilitates a more efficient and cost-effective manufacturing process.
It is another object of the present invention to provide a flexible interdental toothbrush which includes a plurality of concentric grooves for preventing undesirable protrusion of the twisted wire stem from the neck of the brush handle during the manufacturing process.
It is another object of the present invention to provide a flexible interdental toothbrush which includes sufficient spacing between the outer surface of the neck of the handle and the wire brush stem.
It is another object of the present invention to provide a flexible interdental toothbrush which reduces the scrap level during the manufacturing process and thereby reduces operating costs by substantially eliminating the sorting process for defective brushes.
Other objects and advantages of the invention will appear hereinafter.